1. Field
The present invention is related to phased-array antennas and, more particularly, to low-cost active-array antennas for use with high-frequency communication systems.
2. Related Art
Phased array antennas (“PAA”) are installed on various mobile platforms (such as, for example, aircraft and land and sea vehicles) and provide these platforms with the ability to transmit and receive information via line-of-sight or beyond line-of-sight communications.
A PAA, also known as a phased antenna array, is a type of antenna that includes a plurality of sub-antennas (generally known as array elements of the combined antenna) in which the relative amplitudes and phases of the respective signals feeding the array elements may be varied in a way that the effect on the total radiation pattern of the PAA is reinforced in desired directions and suppressed in undesired directions. In other words, a beams may be generated that may be pointed in or steered into different directions. Beam pointing in a transmit or receive PAA is achieved by controlling the amplitude and phase of the transmitted or received signal from each antenna element in the PAA.
The individual radiated signals are combined to form the constructive and destructive interference patterns of the PAA. A PAA may be used to point the beam rapidly in azimuth and elevation.
Unfortunately, PAA systems are usually large and complex depending on the intended use of the PAA systems. Additionally, because of the complexity and power handling of known transmit and receive (“T/R”) modules, many times PAA are designed with separate transmit modules and receive modules with corresponding separate PAA apertures. This further adds to the problems relating to cost and size of the PAA. As such, for some applications, the amount of room for the different components of the PAA may be limited and these designs may be too large to fit within the space that may be allocated for the PAA.
Therefore, there is a need for an apparatus that overcomes the problems described above.